If I'm following this, the question is whether to mount the cover brackets to the plastic FF frame with "sheet metal" or "machine screws" with nuts.
I added MaxxAir-II covers to our FF's and doggedly took the FF's far enough apart to use the machine screws, nuts, and washers they provided in the hardware kit. Nuts worked loose. I spoke with a tech who said he just uses sheet metal screws and has not had problems.
Unfortunately, some "techs" aren't very careful and strip things out using power tools. Sometimes they grab screws that are too big, too small, too long, too short. I'd like to hire more work out. Then I see the results and wand to do more work myself.
